In systems of this type the tentering chains carry tenter bodies which in turn support the above mentioned tentering hooks or clamps. Additionally, the tenter bodies carry guide rollers which run along guide surfaces of the guide rails of the system. The tenter bodies are pivoted to the chain links and it is desirable that the chain pitch is adjustable. The term "chain pitch" in this context means the on-center spacing between two chain bolts that pivot or journal neighboring chain links and tenter bodies to each other.
A tentering chain as described above is known, for example, from U.S. Pat. No. 4,890,365 (Langer) corresponding to German Patent (DE) 3,716,603. The tentering chain disclosed in the just mentioned publications has a continuously adjustable pitch, whereby the adjustment is accomplished by means of bellcranks which interconnect neighboring chain links. Tilting of the bellcranks adjusts the chain pitch. However, such tilting of the bellcranks is limited, so that the chain pitch can only be changed within a narrow range of about 1.5% of the normal chain pitch. At the same time, however, the dimensions of the known tentering chain are quite substantial so that, for example, the pitch itself was 7.5 inches and it is difficult to make this pitch smaller in a conventional chain.